Lightweight Flywheel For Autocross

[SJ Lambert]

Thanks Vaughan

But, I've got the 90 tooth Renault Dauphine ring gear in hand, will fit a Dave Bean supplied clutch friction surface insert into flywheel and Dad will machine it to suit converted BDJ crank. - So, apart from being smaller OD than the 104 tooth Dave Bean flywheel we're using on the McCoy Twin Cam engine, this one will be a very similar spec to the ones Dave Bean produces.

Looks like a square foot of aluminium from which to rough it out will be around $150.


Will use in conjunction with the lightest weight AP (A ring) clutch assembly to minimise inertia (Lucky the flywheel is being done in house - don't want to have to keep buying clutch assemblies!!).

Cheers

James

[SJ Lambert]

The new flywheel, looking a bit out of round just at the minute!!!!

[SJ Lambert]

Gosh, the lightweight clutch to accompany the light weight flywheel sure feels very light!!

[vstibbard]

I just bought lovel ally one from Joseph at chequered flag, see business listing. Takes std clutch assembly so good for street etc, he makes different bolt patterns.

[twincamman]

My experience with light fly wheels is ....you get the jump out of the corner with a light one but on long straights the heavier fly wheel car will carry more speed at the end of the long straights as at Mosport .Watkins on short tracks Shannonville or Nelson Ledges they work fine ...ed

[SJ Lambert]

Affixing these aluminium flywheels to the cranks is now a live topic. The twin cam set up is a 12 bolt affair, so I'm thinking Unbrakos, perhaps with a hardened steel all around one piece plate underlaying it?

I'll check with supplier, Dave Bean, as I suspect he'll say the plate is unecessary but washers or bolt heads will dig into the aluminium at some point.......

The little flywheel will go onto a six bolt crank, so can use bolts with larger heads on that one.

Cheers

James

[Jeff@Jae]

If the Elan is using a standard clutch pressure plate you can probably achieve as much reduced inertia by just lightening the standard flywheel removing that big chunk of weight on the cylinder block side of the flywheel out by the ring gear. Remember, the total weight of the flywheel is less important than where the weight loss is, further from the crank center line the bigger the change in inertia. With a standard pressure plate there is a diminishing return because it is also a flywheel. Now you if you add a smaller diameter racing clutch then you can further reduce the inertia and also make the flywheel even lighter. I prefer the lightweight steel flywheels myself, less trouble in the long run and they are very nearly the same weight, and in some cases lighter, than aluminum flywheels and they have less weight away from the center. I have an aluminum flywheel in my Elan, because it was handy and only slightly used(cheap) to replace the original because someone welded on the ring gear (?) so it was junk. I notice the light flywheel mostly in heel/toe downshifts, the synchros match instantly.

[cabc26b]

One of the cars has an aluminum flywheel with race clutch . i can't vouch for long straight performance difference, but can tell you that drive off is more difficult with alu set up , it is a real pain on the street ( need to look at the master to make sure i got a 5/8" ) . spin up however is everything you would hope for.

george